Technical Abstract:
Cryptosporidium parvum is a protozoan parasite that is a major cause of diarrheal illness in both humans and neonatal calves. Previous studies in humans and mice have suggested that use of probiotics in the form of lactic acid bacteria may be of benefit in reducing infection with C. parvum. Groups of calves (n=5/group) were treated at birth with oral doses of lactic acid bacteria, with or without killed C. parvum vaccine, or received no treatment (controls). Calves receiving lactic acid bacteria continued to receive it twice daily for 10 days. All calves were orally inoculated with 10**4 viable C. parvum oocysts at 3 days of age. Diarrhea and oocyst shedding was monitored and recorded for all calves. Control calves had diarrhea for a mean of 5 days and shed oocysts for a mean of 5.6 days. Calves receiving lactic acid bacteria had diarrhea for a mean of 12 days (significantly longer than controls) and shed oocysts for a mean of 6.4 days. Calves receiving both lactic acid bacteria and C. parvum vaccine had diarrhea for a mean of 9.8 days and shed oocysts for a mean of 4.6 days. Thus, in this trial, no benefit was seen from treatment with lactic acid bacteria. While diarrhea in the treated groups lasted longer than in controls, the protracted phase was not severe, and differed from the typical watery diarrhea characteristic of C. parvum infection.